This lecture covers the RSA encryption algorithm, focusing on its application for privacy and digital signatures. The instructor explains the inverse map, the extended Euclid's algorithm, keys generation, and how decoding works in RSA. The lecture also delves into possible attacks on RSA, the trapdoor one-way function behind RSA, hash functions, and widely-used cryptographic standards. Practical examples, such as encrypting and decrypting with RSA, and how Apple uses RSA for iMessages, are discussed.